This invention relates to an internal combustion engine manifold apparatus for atomizing, during cold startups, a fuel blend containing gasoline and alcohol. More specifically, it relates to a tubular member having a plurality of specially designed orifices for atomizing the blended fuel under cold conditions and also relates to the orientation of the orifices in the manifold as well as the process of forming them.
Environmental concerns about hydrocarbon emissions from gasoline powered vehicle engines have led to the widespread use of petroleum fuels containing methanol. One of the problems encountered in using a gasoline-methanol blend of automotive fuel is that the methanol component of the fuel will not vaporize readily when the engine is cold and the ambient temperatures is below 32 degrees F. As a result engines using blended fuel containing alcohol were difficult to start when subjected to these conditions. The severity of the problem became worse when the percentage of methanol in the fuel was increased or the temperatures decreased.
Accordingly, it is a general object of this invention to provide an atomizing apparatus for injecting into the combustion air stream of an engine a supplemental amount of atomized fuel, in the form of a partially vaporized mist prior to its entry into the engine cylinder. It is another object of this invention to provide an orifice configuration which efficiently atomizes the fuel blend. It is still another object of this invention to further enhance vaporization of the fuel blend by maximizing the residence time of the atomized mist in the flow of combustion air in the manifold. It is yet another object of this invention to provide a simple and economic method for producing the desired orifice configuration in a tubular member.